Technical Question Bank · Peer-Reviewed
Search and filter frequently asked interview questions across technical, programming, and behavioral domains. Tailor your interview preparation by difficulty for freshers or experienced developers (1,236 available).
When you want to access `this.props` in `constructor()` then you should pass props to `super()` method. **Using `super(props)`:** ```javascript class MyComponent extends ...
You can't use setTimeout(fn, 0) to execute the code immediately due to minimum delay of greater than 0ms. But you can use window.postMessage() to achieve this behavior.
When you use `setState()` the current and previous states are merged. `replaceState()` throws out the current state, and replaces it with only what you provide. Usually `...
The `componentDidUpdate` lifecycle method will be called when state changes. You can compare provided state and props values with current state and props to determine if ...
The better approach is to use `Array.prototype.filter()` method. For example, let's create a `removeItem()` method for updating the state. ```javascript removeItem(index)...
It is possible. Below are the possible options: ```jsx harmony render() { return false } ``` ```jsx harmony render() { return true } ``` ```jsx harmony render() { return ...
1. **Calling `setState()` with an object to merge with state:** - Using `Object.assign()` to create a copy of the object: ```javascript const user = Object.assign({}, thi...
It is known that not all JavaScript libraries or frameworks have TypeScript declaration files. But if you still want to use libraries or frameworks in your TypeScript fil...
There are approaches to include polyfills in create-react-app, 1. **Manual import from `core-js`:** Create a file called (something like) `polyfills.js` and import it int...
You just need to use `HTTPS=true` configuration. You can edit your `package.json` scripts section: ```json "scripts": { "start": "set HTTPS=true && react-scripts start" }...
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